Method for making castings



United States Patent 72] Inventor Russell W. Taccone 3,300,823- 1/1967Tuttle...........................

Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. BrownErie, Pennsylvania 871,042

21 Appl. N0.

Division ofSer. N0. 674,044, Sept. 18, 1967 A nomey Hamess Dickey andPierce 8 7 1 5 mm m a M P aw S d h F 1 2 2 i [45] Patented Nov. 17,1970

An apparatus and method for making castings of successively forming adrag of a compacted green sand mixture having a cavity therein of apreselected pattern and disposed in an open ended flask, successivelytransferring the flasks by a transfer device into alignment with theinlet end of a casting tube adapted to guidably support a plurality ofthe molds disposed in face-to-face abutting relationship and pressingthe mold from the flask in a manner to effect a trimming of theperiphery of the mold to correspond 164/137 with and to rovide a slidinsealin fit with the inner surface P 8 g of the casting tube, pouringmolten metal into the cavities of 4 the molds while disposed in stackedface-to-face abutting relationship within the casting tube 'andthereafter successively ejecting and transferring the filled molds to anelongated cpolingtube provided with cooling means for accelerating the1500 H623 77,391.11 2 9 442 MM 26 ,1 B 3 1 a .31 m 7'5 25 m 22 .m 4 4 85U 12 m 3 85 a 12 m 1 4 N 84 uh 7 9 632 "M13 m&5 oo 62 L0 3 d .1 ale .1hr. 11 0 55 [.1

Referel'lces Cited removal of heat from the molds. ln some aspects ofthe ap- UNITED S ATES PATENTS paratus and method comprising the presentinvention, a subatmospheric pressure is applied to the periphery of themolds while in ,the casting tube for removing gaseous products formedduring the casting operation. An improved mold is alsodscribed whichconsists of a mass of compacted green 164/22 sand having a core of athin walled shell of bonded sand disposed in overlying relationshipon'one face thereof provid- X 7 ,3 1 MM. 6 1

ing porosity and precision in castings heretofore unobtainable.

Patented Nov. 11,1970 3,540516 Sheet L of 5 1N VE NYUR.

Patented Nev. 17, 1970 3,540,516

Sheet 2- of5 INVENTOR.

Patented Nov. 17, 1970 Sheet 4- of 5 INVENTOR. i/Z/Q'ZZ/ A/ lim /z BYfiMm/ W34 47 'm/Vn/r/f Patented Nov. 17, 1970 I 3,540,515

/44 1 i; AM

INVENTOR.

METHOD FOR MAKING CASTINGS CROSS REFERENCE TO RELATED APPLICATIONS Thisapplication is a divisional application of copending application Ser.No. 674,044, filed Sept. 18, 1967, now US Pat. No. 3,517,728 forApparatus for Making Castings, which is assigned to the same assignee asthe present invention.

BACKGROUND OF THE INVENTION New materials and manufacturing techniqueshave occasioned a revolution in foundry practices for making molds andmetal castings. The impetus of automation and new sandbonding materialshas enabled major changes to occur in the foundry for manufacturingmolds and metal castings at a rate and of a quality heretoforeconsidered unattainable. Of the various processes heretofore used orproposed for use, only relatively few have been given commercialconsideration due to various disadvantages either in the mold makingphase or in the speed and quality of the castings produced thereby. Forexample, in prior art processes proposing the use of stacked molds,limitations on the residence time of the cast metal in the mold cavitieshas caused a limitation in the speed of mold production and castingmanufacture or, alternatively, has caused excessive compressive loads tobe imposed on the molds causing distortion and fracture thereof with acorresponding distortion or imperfection in the resultant cast part. Theeconomic advantages attending the manufacture of precision castingswhich substantially reduce the number and duration of further machiningoperations has occasioned a need for improved foundry techniques incomparison to those heretofore proposed.

The apparatus and method comprising the present invention provide thecombined benefits of a high speed mold making and casting operationnecessitating minimal labor and c0ntrol with the ability of producingprecision castings requiring only minimal additional machining formanufacturing a finished product.

SUMMARY OF THE INVENTION The foregoing and other objects and benefits ofthe present invention are achieved by an apparatus and a method for making sand molds and metallic castings wherein the preliminarily formedmolds are successively pressed from an open ended mold box or flask intothe inlet end of an elongated casting tube that has a cross-sectionalsize smaller than that of the cross-sectional size of the mold.Accordingly, a trimming or shaving of the mold occurs wherein it ispositioned in precise registration with the inner surface of the castingtube assuring proper registry of the mold pattern therein. In addition,the molds are preferably constructed so as to incorporate channels orapertures therethrough disposed in communication with the mold cavityand the periphery of the mold whereby subatmospheric pressure can beapplied to the mold cavity for withdrawing any gases evolved or producedduring the delivery of molten metal into the mold cavity. The apparatusand method are applicable to so-called two-piece molds comprising apaired cope and drag which define between the mating surfaces thereof acavity of a preselected pattern, individual molds having preselectedconfigurations on the opposed faces thereof which, when disposed inface-to-face abutting relationship form at their adjoining facescavities ofa preselected configuration; and individual moldsincorporating in one face thereof a depression overall or a portion ofwhich a precision thin wall shell-type core is disposed defining acavity of an accurate configuration. The successive pressing of moldsinto the casting tube in which the molds are filled with molten metal isaccompanied by an intermittent and successive ejection of a filled moldfrom the exit end of the casting tube which, by a transfer device, istransferred into alignment with alternate ones of a' plurality ofcooling tubes in which the molds are successively stacked enabling aproper degree of cooling thereof. The resultant cooled molds aresuccessively junction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view partlydiagrammatic illustrating an arrangement of the apparatus in accordancewith one embodiment of the present invention for making two-piece pairedmolds;

FIG. 2 is a fragmentary side elevational view of a transfer deviceincorporating an ejector thereon positioned in a loading position;

FIG. 3 is a fragmentary side elevational view similar to that shown inFIG. 2 with the transfer device in the operative position for pressing amold from a flask into the inlet end of the .casting tube;

FIG. 4 is a transverse sectional view through a mold comprising a copeand drag and a core disposed in open ended paired flasks prior toinjection into the casting tube;

FIG. 5 is a perspective view partly diagrammatic illustrating anapparatus for making molds employing individual sand molds and precisioncores in accordance with an alternative embodiment of the presentinvention;

FIG. 6 is a fragmentary longitudinal sectional view of a plurality ofsand molds incorporating precision cores disposed in face-to-faceabutting relationship in the casting tube;

FIG. 7 is a transverse vertical sectional view through the mold andcasting tube shown in FIG. 6 and taken along a line 7-7 substantiallyadjacent to the mating faces of adjacent sand molds;

FIG. 8 is a fragmentary side elevational view partly in sec-,

DESCRIPTION OF THE PREFERREDEMBODIMENTS Referring now in detail to thedrawings and as may be best seen in FIG. I, an illustrative embodimentof the present invention comprises an integrated apparatus for makingmolds and transferring them over suitable conveyor means to a transferdevice which in turn is operative for injecting the molds into the inletend of a casting tube. The specific apparatus as illustrated in FIG. 1,is applicable for forming sand molds of the type comprising two moldhalves designated as a drag and cope which are adapted to be pairedtogether incorporating a suitable core, if desired for forming a moldcavity of a requisite configuration. A typical mold of this type isillustrated in FIG. 4.

The apparatus as illustrated in FIG. 1, comprises a belt or othersuitable conveyor 20, which moves in the direction of the arrow fortransferring mold boxes or drag flasks 22 to the inlet side of a dragmolding machine 24. The drag molding machine includes a base 26 on whicha pattern board 28 is supported for providing an appropriate depressionof a preselected configuration in a sand mold. The drag molding machineincludes a suitable ram 30 for compacting a green sand mixture of any ofthe types well known in the art, within the interior of the drag flask22 when disposed in overlying registered relationship on the patternboard 28. The drag flask having the compacted and contoured sand mixturetherein is stripped from the pattern board 28, and thereafter passesfrom the drag molding machine into an inverter or'roll-over device 32,whereby the drag flask is rotated to an inverted position and passesalong a conveyor 34 in the direction of the arrow along a core settingarea as indicated in FIG. 1. In the core setting area, an operator or anapparatus (not shown) is effective to insert a core in the cavity formedin the drag for a purpose well known in the art. The drag flasksthereafter pass into a closing machine 35 in which each drag flask isaligned and united with a cope flask 36.

The cope flasks or mold boxes 36 are similarly filled with a compactedgreen sand mixture in response to being moved by a conveyor 38 into theinlet side of a cope molding machine 40 including a base 42 on whichsuitable pattern boards 44 are mounted. The interior of the cope flasks36 are similarly filled with a compacted green sand mixture, after whichthey are transferred by a conveyor 46 to the closing machine 35.

The closing machine 35 performs the function of pairing a filled dragflask with a filled cope flask in appropriate relative alignment,whereafter each paired assembly is transferred on a conveyor 48 to atransfer device 50. The aligned relationship of the filled cope flaskand filled drag flask is best seen in FIG. 4. As shown, the drag flask22 and cope flask 36 are formed with laterally extending webs 52 forengagement with aligning means on the transfer device subsequently to bedescribed. The mating flange 54 on the drag flask is provided with a1ongitudinally extending pin 56 which is adapted to be disposed inbearing contact with the surface of a bore 58 formed in a correspondingmating flange 60 on the cope flask 36. In accordance with thisarrangement, appropriate registration of the sand cope 62 is maintainedrelative to the sand drag 64 and a preshaped core 66 disposedtherebetween.

As will be noted in FIG. 4, the opposing faces of the core 66 and thedrag 64 define a cavity 68 which is adapted to receive molten metal forforming a casting of a corresponding configuration. In the specificembodiment illustrated in FIG. 4, the drag is formed along its matingface with a sprue 70 through which molten metal is adapted to beintroduced into the cavity 68. In accordance with a further embodimentof the present invention, the mating faces of the cope 62 and/or drag 64are provided with a plurality of radial grooves 72 which extend from aposition in communication with the cavity 68 to a position incommunication with the periphery of the mold. The radial grooves 72 areofa diameter which provide free access for the escape of gases from themold cavity which are formed during the casting operation but are ofasize which inhibits the passage of molten metal therethrough. Theprovision of such radial grooves also enables the application ofsubatmospheric pressures to the mold, cavity facilitating the withdrawalof gaseous constituents therefrom and thereby assuring a resultant castarticle substantially devoid of any blow holes or pockets therein.

In the exemplary embodiment as shown in FIGS. 1 through 4, theconfiguration of the cavity corresponds to that ofa dishshapedcylindrical object which is typical of a vehicle brake drum. Inaddition, the drag 64 and cope 62 are of a circular configuration but itwill be appreciated that alternative mold cavity shapes and otherregular or irregular peripheral mold shapes can also be satisfactorilyemployed in the practice of the present invention.

The transfer device 50, as shown in FIGS. 1 through 3, is movable from aload position as shown in FIG. 2 to an operative position angularlytilted from the load position corresponding to that shown in FIG. 3. Inthe load position shown in FIG. 2, the bed 74 of the transfer device isoriented in alignment with the conveyor 48 (FIG. 1) so as to receivepairs of cope and drag flasks filled with compacted green sand. The bed74 is pivotally mounted on a shaft 76 extending longitudinally of theconveyor 48 which in turn is rigidly supported on a framework 77. Thebed 74 is formed at its upper surface as viewed in FIG. 2, with aU-shaped channel to the opposing side surfaces of which flanged rollers78 are rotatably mounted. The flanged rollers 78 are operative to engagethe lower surface and side edges of the web 52 on the drag flask 22maintaining it in appropriate vertical and lateral position. Similarly,the upper edges of the U-shaped portion of the bed 74 are formed withopposing notched engaging arms 80 which are adapted to overlie the upperedge surfaces of the webs 52 of the cope flask 36. A suitable stop 82 isalso provided for maintaining the cope and drag flask assembly inappropriate lateral relationship relative to the bed of the transferdevice.

Movement of the transfer device from the load position as shown in FIG.2 to the operative position as shown in FIG. is achieved by adouble-acting fluid actuated cylinder 84 having its blank end pivotallyconnected to a bracket 86 affixed to the framework 77 and its piston rod88 connected by means of a clevis type fitting 90 to a pin 92 affixed tothe bed 74 at a point spaced from the shaft 76. A suitable source (notshown) of a pressurized fluid is provided for alternately causing thepiston rod 88 to reciprocate from the position shown in FIG. 2 to theposition as shown in FIG. 3. Energization of the cylinder 84 can beachieved manually or automatically in accordance with means well knownin the art.'

In response to energization of the cylinder 94, the transfer devicemoves toward the operative position as shown in FIG. 3 and suitable coacting means are provided adjacent to the inlet end of a pouring orcasting tube 94 for orienting the axis of the cope and drag flasksrelative to the axis of the casting tube. In the exemplary embodimentillustrated the coacting means comprise a pressure pad 96 affixed to theupper leg of the U shaped portion of the bed 74 which is adapted to bedisposed in firm abutting relationship against a stop pad affixed to abracket 100 mounted on the upper surface of the casting tube.

Suitable cushioning means comprising a cylinder 102 mounted on thebracket 100 and adapted to coact with a pin 104 on the bed adjacent tothe pressure pad 96 are provided for eliminating the shock ofengagement. A similar cushioning assembly comprising a cylinder 106 anda pin 108 is provided for absorbing any shock loading during themovement of the transfer device to the load position (FIG. 2).

With the transfer device in the operative position as illustrated inFIG. 3, the cope and drag are concurrently pressed from the interior ofthe cope flask 36 and drag flask 22 and are transferred into the inletend of the casting tube 94. This transfer is accomplished by means of anejector comprising a pressure pad 110 affixed to the end of a piston rod112 of a press cylinder 114 which is securely attached to brackets 116on the bed 74 of the transfer device. In accordance with this mountingrelationship the thrust axis of the pressure pad or ram 110 is inalignment with the axis of the casting tube 94 when the transfer deviceis in the operative position assuring a smooth transfer of the compactedcope and drag into firm sliding engagement and guided relationshipwithin the interior of the casting tube 94. At the completion of thepressing motion of the ejector, the pressure pad or ram 110 is againreturned to the retracted position and the cylinder 84 is actuatedwhereby the transfer device returns to the load position as illustratedin FIG. 2. In that position subsequent movement of the conveyor 48 iseffected to discharge the empty cope and drag flasks from the transferdevice and replace it with a paired drag and cope flasks filled withsand and the operation is again repeated.

Referring back to FIG. 1, the empty cope and drag flasks are conveyed bythe conveyor 48 in the direction of the arrows to a separator 118 whicheffects a disengagement of the two flasks and a return thereof to theinput side of the drag molding machine and cope molding machine forrefilling with green sand in a manner as previously described.

The apparatus hereinbefore described with modification, is equallyapplicable for effecting the rapid production of individual moldsincorporating precision shell-type cores which are transferred in asimilar manner into the inlet end of a casting tube in accordance withthe arrangement as illustrated in FIG. 5. In this arrangement dragflasks 120 which similarly are open ended mold boxes, are conveyed on aconveyor 122 into the input side of a drag molding machine 124. Patternboards 126 mounted on the base of the machine are sequentially orientedwith an overlying drag flask which in turn is filled with sand andcompacted so as to provide a depression of a preselected configurationconforming to the pattern on the pattern board. The filled drag flask120 is thereafter stripped from the pattern board and passes through aninverter or rollover device 128 in which it is inverted 180 andthereafter is conveyed on a conveyor 130 along a core setting area asindicated in FIG. 5. In the core setting area, precision-type cores,subsequently to be described, are manually or mechanically inserted inthe cavities of the filled drag flasks, which thereafter are conveyed toa transfer device 132 of the same construction as previously describedin connection with FIGS. 2 and 3. The transfer device 132 effects apressing of the drag and precision core out through the open end of thedrag flask 120 and into the inlet end ofa casting tube 133 in a manneras previously described. The empty drag flasks at the completion of thepressing operation are returned by the conveyor 122 to the input side ofthe drag molding machine for a refilling thereof with compacted greensand.

The specific construction of the individual molds is best seen in FIGS.6 and 7. As shown in these two FIGS., a drag 134 of a compacted greensand is disposed with the periphery thereof in sliding bearing contactagainst the inner surface of the casting tube 133. One face of the drag134 is disposed in firm abutting relationship against the adjacent faceof a similar drag, forming a stacked series of molds within the pouringtube in which they are guidably and-slidably disposed. In the exemplaryembodiment shown in FIG. 6, the drag 134 is formed with a dish-shapeddepression 136 extending inwardly from one face thereof which, incombination with the face of the adjacent mold, define an annularshoulder 138 in which a peripheral flange 140 of a precision thin-walledshell-type core 142 is seated and is disposed in appropriate registeredrelationship relative to the dish-shaped depression 136.

The drag 134 is further formed at its upper end as viewed in FIGS. 6 and7 with a sprue which is adapted to be exposed through an elongated slotI44 provided along a portion of the upper surface of the casting tube133. In the exemplary embodiment illustrated, the sprue extendsdownwardly into an arcuately-shaped gate 146 for distributing the moltenmetal along at least a portion of the periphery of a mold cavity 148 asdefined by the opposing surfaces of the precision core and depression.The adjacent face of a second drag is preferably provided with aradially extending depression or aperture 150 which is disposed incommunication with the outer surface of the precision coreand with theperiphery of the drag for venting the interior of the mold. Inaccordance with a preferred embodiment of the present invention, thecasting tube, as best seen in FIG. 7, is provided with a plurality ofapertures or ports 152 in the wall thereof which are disposed incommunication with a chamber 154 to which a subatmospheric pressure isapplied. Accordingly, by this arrangement, gaseous products present, orproduced during the casting operation, are quickly removed from the moldinterior out through the aperture to the vacuum chamber, substantiallyenhancing the rapid filling of the mold cavity 148 and further assuringsuccessive, accurate high-quality castings.

A further advantage of the mold construction as illustrated in FIGS. 6and 7 is the permeability as provided by the shelltype core and theaccurate surface contour ofits face, defining a portion of the moldcavity. It is known that compacted green sand mixtures leave much to bedesired with respect to their permeability characteristics, and, as aresult, frequent entrapment of gaseous components occurs which detractsfrom the quality of the castings produced and substantially increasesthe scrap percentage of articles made. In accordance with the moldconstruction as illustrated in FIGS. 6 and 7, the use ofa relativelypermeable and accurate shell-type core substantially facilitates theescape of gaseous products from the mold cavities, while concurrentlyproviding for a resultant surface finish requiring only minimal furthermachining.

In the specific mold constructions as illustrated in FIGS. 6 and 7, itwill be noted that the surface of the shell type core 142 defines theinner surface of a brake drum, whereas the surface defined by the dragrepresents the outer surface of the brake drum, which normally does notrequire further machining. The increased accuracy provided by theshell-type core necessitates only minimal machining operations toprovide a true cylindrical surface necessary for satisfactory operationof wheel-type brakes.

Thin-walled, shell-type cores corresponding to the can; 142, as shown inFIGS. 6 and 7, are manufactured by techniques well known in the artemploying a sand or sand mixture incorporating from about 1 percent upto about. 10 percent of a suitable sand binding agent. Sand binding a eof this type usually are selected from thermosetting resins, such asphenolaldehyde resins, urea formaldehyde resins, furfuryl resins,furfuryl aldehyde resins, etc., as well as mixtures and copolymersthereof. The sand mixture incorporating the thermosetting resin binderis conventionally applied to a heated pattern generally by blowing thesand binding mixture incorporating a suitable catalyst against theheated pattern. The heat of the pattern causes initiation of the curingreaction of the sand binding agent, whereby after a preselected timeperiod, the sand shell is stripped from the pattern and either subjectedto further curing or allowed to cool prior to further use.Precision-type cores made in accordance with the shell molding processwell known in the art can'be satisfactorily employed in the practice ofthe present invention for making various articles of differentconfiguration and providing both the benefit of accuracy andpermeability.

Regardless of whether a two-piece mold or an individual mold is employedfor receiving the molten metal, the molds,

upon entering the casting tube, are disposed in a stacked faceto-faceabutting relationship and are intermittently advanced therethrough inresponse'to the pressing of a new mold into the inlet end of the castingtube. Concurrently, upon the entry of an additional mold, a mold filledwith metal is ejected from the outlet end of the casting tube. In orderto provide greater accuracy and assure optimum alignment of the stackedmolds relative to each other in the casting tube, the cross-sectionalsize of the casting tube is of a controlled smaller size than theperipheral size of the mold being pressed therein. This rela tionship isbest illustrated in FIG. 8. As shown, the casting tube 133 is providedat its inlet end with a scraper blade or knife 156 for trimming theperiphery of the drag 134 of an individual-type mold incorporating aprecision shell-type core 142 in response to the inward movement of themold. The pressing operation is achieved by the pressure pad I10 affixedto the piston rod 112, whereby the drag and core are concurrentlyejected from the drag flask disposed in appropriate alignment withrespect to the inlet end of the casting tube. The shaving operationresults in the trimming of excess sand particles as indicated at 158,whereby a substantially improved iii of the stacked molds is achievedwithin the casting tube.

While the molds-are positioned in the casting tube of the apparatusesillustrated inFIGS. l and 5, molten metal is poured from a suitableladle 160 through the sprues and intothe cavities therein. The metalpouring operation can be achieved manually or automatically, as desired.

Due to the frictional resistance presented by the engagement of theperiphery of the molds with the inner surface of the casting tube, thelength of the casting tube is of necessity limited to enableintermittent advancement of the mold through the tubes without requiringexcessive force which would effect a crushing, fracture or distortionthereof. In accordance with a further embodiment of the presentinvention, a second transfer device 162 is provided at the end of thecasting tubes as illustrated in FIGS. 1 and 5, which is formed with achamber 164 therein for receiving a mold 166 discharged from the outletend of the casting tube when in aligned position relative thereto. Thetransfer device, as best seen in FIG. 9, is pivotally mounted on a shaft168 extending longitudinally of the axis of the casting tube and ispivotable to and from a loading position as shown in solid lines in FIG.9 to alternative unloading positions in which the chamber 164 and a mold166 therein are aligned with the inlet ends of coolingtubes 170extending in laterally offset parallel relationship relative to thecasting tube.

When the transfer device is in either of the alternative unloadpositions as illustrated in FlG. 9, the mold 166 therein is pressed fromthe chamber 164 by means of ejectors 192, as shown in FIGS. 1 and 5,mounted along each side of the casting tube. Each of the ejectors 192consists of a double-acting fluid-actuated cylinder 194 having apressure pad 196 affixed to the end thereof and which is reciprocable toand from a retracted position as shown in solid lines in FIGS. 1 and 5to a projected position in which the face of the pressure pad isdisposed contiguous to the inlet end of the cooling tube.

, Movement of the transfer device from the load position to the unloadposition is achieved by a double-acting transfer cylinder 172 having itsblank end pivotally affixed to a bracket 174 and its piston rod 176connected to a pin 178 on the transfer member disposed in spacedrelationship relative to the axis of the shaft 168. Appropriateregistration of the chamber and mold of the transfer device with theinlet ends of the cooling tube is achieved by mechanical stops 180affixed to each cooling tube, which are adapted to coact with pressurepads 184 affixed to each side of the transfer device. Orientation of thetransfer device relative to the load or upright position, as shown inFIGS. 1, 5 and 9, can be suitably achieved by a limit switch 186 which,upon actuation, is operative to deenergize further movement of thepiston of the transfer cylinder 172.

As best seen in FIG. 9, the cooling tubes 170 are preferably of ahollow-walled construction defining a chamber 138 into which a suitablecooling fluid, such as air or water, can be circulated for enhancing therate of cooling of the mold. The cooling fluid can suitably beintroduced into the chamber 188 by means of conduits 190 disposed incommunication with the interior of the chambers and connected to asuitable source of cooling fluid. The passage of cooling fluid ispreferably done in a counter current flow.

The molds, upon being ejected from the end of the cooling tubes, arehandled in a conventional manner whereby the castings are extracted fromthe molds and the usable sand is recycled back to the drag and copemolding apparatus for mixture for fresh makeup for reuse.

While it will be apparent that the invention herein disclosed is wellcalculated to fulfill the objects above stated, it will be appreciatedthat the invention is susceptible to modification, variation and changewithout departing from the proper scope or fair meaning of the subjoinedclaims.

lclaim:

1. A method for making castings which comprises the steps ofsuccessively feeding sand into open ended flasks forming molds havingcavities therein ofa preselected pattern, succezsively positioning saidflasks adjacent to and in alignment with an open'e'nded elongatedcasting tube, pressing said mold from said flask into one end of saidcasting tube effecting a trimming of the periphery of said mold toconform with the cross-sectional configuration of said casting tube inresponse to the inward movement of said mold, continuing the aforementioned steps until said casting tube incorporates a plurality of saidmolds each disposed in face-to-face mutual abutting, relationship,pouring molten metal into the cavities of said molds, successivelyejecting a filled mold from said casting tube and transferring said moldin stacked relationship into a cooling tube, applying a cooling fluidaround the periphery of said molds while in said cooling tube toaccelerate the removal of heat therefrom, and thereafter successivelyejecting the molds from the cooling tube and removing the castingtherefrom.

2. The method as defined in claim 1, further characterized by the stepof applying subatmospheric pressure to the periphery of the molds whilein said casting tube for extracting gaseous products therefrom.

3. The method as defined in claim 1, further including the steps offorming communicating apertures in the face surface of said molds forfacilitating the withdrawal of gases from the cavities therein.

4. The method as defined in claim 1, further characterized by the stepsof independently forming a thin-walled shell of a bonded sand mixture ofa preselected configuration defining a core, placing said core inappropriate registry and in overlying relationship with respect to oneface of said mold while disposed in said flask in a manner such that theopposing face surfaces of said core and said mold define a cavity ofpreselected configuration,

